Table 2 Comparison of the sprint force-velocity profile between the different time points of the season and age categories.

From: Seasonal changes in the force velocity sprint profile of Spanish youth football players across age categories

 

Period 1

Period 2

Period 3

U10

U12

U14

U16

U18

U10

U12

U14

U16

U18

U10

U12

U14

U16

U18

F0 (N)

195.6 ± 19.6bcd

241.7 ± 19.5bcd

323.0 ± 17.1#

344.6 ± 20.4*#

356.6 ± 23.6*#

192.6 ± 20.2bcd

223.289 ± 22.258bcd

307.2 ± 17.7#cd

442.5 ± 21.1#

463.7 ± 24.3

208.8 ± 18.1bcd

247.1 ± 19.2bcd

354.9 ± 15.9d

400.1 ± 18.9

474.6 ± 21.8

F0 (N/kg−1)

6.1 ± 0.2

6.4 ± 0.2c

6.8 ± 0.2 cd

5.3 ± 0.2*#

5.4 ± 0.2*#

5.8 ± 0.2

5.7 ± 0.2

6.3 ± 0.1#

6.6 ± 0.2

6.7 ± 0.2

6.3 ± 0.2

6.3 ± 0.2

7.0 ± 0.2

6.1 ± 0.2

6.8 ± 0.3

VO (m/s−1)

6.1 ± 0.1bcd

6.4 ± 0.1#bcd

7.3 ± 0.1 cd

9.0 ± 0.1*

9.2 ± 0.2*

6.3 ± 0.1bcd

6.3 ± 0.1#bcd

7.3 ± 0.1 cd

8.3 ± 0.1#

8.6 ± 0.2

6.3 ± 0.1bcd

6.8 ± 0.1bcd

7.6 ± 0.1 cd

8.7 ± 0.1

8.8 ± 01

P max (W)

300.2 ± 36.4bcd

389.5 ± 38.9bcd

594.8 ± 31.9#cd

762.3 ± 37.9*#

817.6 ± 43.8*#

302.3 ± 43.4bcd

353.8 ± 41.2#bcd

568.1 ± 38.0#cd

920.1 ± 45.2

1003.3 ± 52.2

334.4 ± 39.2bcd

424.524 ± 37.284bcd

678.234 ± 34.337 cd

868.823 ± 40.870

1051.450 ± 47.192

P max (W·kg−1)

9.5 ± 0.4bcd

10.3 ± 0.4*b

12.6 ± 0.4

11.9 ± 0.4*#

12.4 ± 0.5*#

9.1 ± 0.4bcd

9.2 ± 0.4#bcd

11.6 ± 0.4#cd

13.7 ± 0.5

14.5 ± 0.5

10.1 ± 0.5bcd

10.890 ± 0.503bcd

13.459 ± 0.489

13.277 ± 0.582

15.249 ± 0.672

FV-slope kg−1

− 1.01 ± 0.03 cd

-0.99 ± 0.03 cd

-0.93 ± 0.03 cd

-0.61 ± 0.03*

− 0.59 ± 0.04*#

− 0.92 ± 0.03

− 0.91 ± 0.02

-0.86 ± 0.02

− 0.80 ± 0.03#

− 0.78 ± 0.04

-0.99 ± 0.03 cd

− 0.92 ± 0.04c

− 0.92 ± 0.03c

− 0.70 ± 0.04

− 0.77 ± 0.04

RFpeak (%)

16.4 ± 0.4bcd

16.7 ± 0.5#bcd

19.1 ± 0.4 cd

23.1 ± 0.4

24.0 ± 0.5

16.6 ± 0.5bcd

16.9 ± 0.5#bcd

1.95 ± 0.4 cd

22.1 ± 0.5#

23.0 ± 0.6

16.4 ± 0.5bcd

18.2 ± 0.4 cd

19.8 ± 0.4 cd

23.3 ± 0.5

23.8 ± 0.5

DRF (%)

10.0 ± 0.4 cd

9.8 ± 0.3 cd

9.2 ± 0.3 cd

5.9 ± 0.4*

5.7 ± 0.4*#

9.2 ± 0.3d

9.0 ± 0.4

8.5 ± 0.3

7.8 ± 0.4#

7.6 ± 0.4

9.9 ± 0.3 cd

9.1 ± 0.3 cd

9.1 ± 0.3 cd

6.7 ± 0.004c

7.5 ± 0.4

  1. Notes: Differences concerning the mentioned group at a (U12). b (U14). c (U16). d (U18) P < 0.05. Differences with respect to the mentioned time in * (moment 2). # (moment 3) P < 0.05. g: grams; %: percentage. N: newton; F: force; kg: kilograms; P: peak; W: watios; FV: force-velocity; %: percentage; F0: theoretical maximal force; V0: theoretical maximal velocity; FV slope: force-velocity slope; Pmax: theoretical maximal power; DRF: decrease in the ratio of horizontal force; RF peak: maximal ratio of horizontal force.